(CNN) -- As one of the nation's leading fertility experts, Dr. Jamie Grifo is barraged with phone calls requesting advice. He thought he'd heard it all until a few weeks ago when callers started asking him a completely new question.

"They want to know when to have sex to have a baby on November 11," says Grifo, program director of the New York University Fertility Center. "11-11-11 - people really want that birth date for their baby."

Grifo's answer: A woman who conceives February 18 will have a November 11 due date, provided she has a regular 28-day cycle. But of course conception is not an advanced science. Since cycles vary and most pregnancies aren't exactly 40 weeks, conceiving a child anytime in the next week or two could get the coveted 11-11-11 digits for your little one. Valentine's Day sex, for example, could very well land you a baby on November 11.

The next chance for a birth date with six numbers all the same? November 11, 2111. You'll be dead by then.

Conception myths or facts: Dirty movies, laptops and sweet potatoes

Whether you're aiming for 11-11-11 or not, you can increase your chances of conceiving by having sex on your most fertile days of the month -- this conception calendar will help determine those days. Beyond that, you should separate fact from fiction when it comes to conception. Does dad need to trade in his tighty whities for briefs to keep sperm in tiptop shape? If mom has an orgasm, will that help sperm reach egg? Are certain sexual positions conducive to conception?

These are all questions Polly Blitzer has been asking herself repeatedly.

Married for more than two years, Blitzer and her husband started trying to get pregnant last summer, but so far no luck. In the meantime, she's 35, not getting any younger and her friends are having babies left and right.

"I feel like I should have a house account at Ralph Lauren for all the monogrammed onesies I send every month," says Blitzer, editor-in-chief of beautyblitz.com.

Her sister-in-law told her to eat sweet potatoes to "make your womb plush." A friend told her to have her husband watch sexy movies as they help produce more sperm. A stranger on an airplane even handed Blitzer her baby, advising that playing with a wee one would help Blitzer's eggs "drop." Another magazine editor told Blitzer, who lives in New York City, to go see an acupuncturist in Chinatown because "he got everyone at Conde Nast pregnant." And in what Blitzer described as the "weirdest" piece of advice, her housekeeper urged her to put her legs up against the wall for half an hour after having sex.

So which of these is right? In honor of, 11-11-11, here are 11 popular conceptions about conception.

1. Myth: Sweet potatoes make a womb "plush."

There are no studies showing sweet potatoes do any such thing, says Dr. Carlene Elsner, a fertility specialist with Reproductive Biology Associates in Atlanta.

Speaking of diet, it does help to keep to a healthy weight. Both anorexic women and obese women are more likely to have fertility problems.

2. Myth: Watching porn increases a man's sperm count.

This one makes Elsner laugh.

"It may increase his interest in having sex, but it's not going to increase his sperm count," she says.

There's an old wives' tale that the missionary position will get the sperm closer to the cervix and hence closer to the egg, but it's just not true, Grifo says.

5. Worth trying: Staying horizontal helps

Staying horizontal after sex might help, since it allows more semen to stay in the vagina, according to the experts at babycenter.com. However, this doesn't mean you'll fail to conceive if you jump out of bed immediately after having sex.

"With millions of sperm in every ejaculation, there should be plenty of sperm in your vagina even if you get up right away," according to the group's website.

6. Worth trying: Get the laptop off dad's lap

In his seminal (pun intended) paper "Increase in scrotal temperature in laptop computer users," Dr. Yefim Sheynkin found that men who use laptops on their laps had higher scrotal temperatures.

This is bad. The reason testicles hang outside the body is that sperm work best when stored 2 to 4 degrees centigrade cooler than core body temperature.

Using a lap pad between dad and the computer won't bring the temperature down, according to a study out this month in Fertility and Sterility by Sheynkin and his colleagues at the State University of New York at Stony Brook. Sheynkin's suggestion: Men should put the laptop on the table, or at the very least use it on the lap for limited periods of time.

7. Worth trying: Boxers instead of briefs

Briefs may have the same warming effect as laptops. For some men, it doesn't matter what they wear. But if a man's sperm aren't behaving up to par, it might be worth making the switch to boxers, says Dr. Shari Brasner, an assistant clinical professor of obstetrics, gynecology and reproductive science at the Mount Sinai School of Medicine in New York City.

8. Myth: Past use of birth control pills makes it tough to get pregnant

Doctors do advise going off the pill about three months before you want to conceive. "By three months, 90% of women are back to ovulating," Brasner says.

9. Myth: You can't get pregnant while nursing

While breastfeeding may make you less likely to get pregnant, it can still happen, Brasner says.

10. Worth trying: Acupuncture can help make you fertile

Some studies -- but not all -- show acupuncture might help infertile women. Even if it doesn't, it couldn't hurt.

11. Myth: If a woman has an orgasm, she's more likely to get pregnant

"Whether a woman has an orgasm doesn't seem to matter," Grifo says. He adds that some studies show it matters for other animals, but no study shows it's true for humans. "The jury is still out on this one, but there's enough evidence for me to say an orgasm is not required for conception," he says. "So don't let that stress you out."

As for Blitzer, she's going to the doctor next month for what she calls a "state of the uterus" exam. In the meantime, she got a puppy in hopes that feeling more maternal will increase her fertility. She knows it's a myth, but she's trying it anyway.